Error in Calculated Dimension

[#1]

Hi all,

I need to use the following expression as a Calculated Dimension:

=FirstSortedValue( aggr(sum(stkh_movement_quantity),stkh_product,stkh_movement_date), -aggr(stkh_movement_date,stkh_product,stkh_movement_date)))

The aim is to give only the most recent movement quantity, based on the latest movement date. It works fine as an expression, however when used as a Dimension I get the //Error in Calculated Dimension. Any ideas where I'm going wrong?

Many thanks for any help.

[#2]

Hey guys, 

I am given a task to calculate the frequency of calls across a territory. If the rep called a physician regarding the sale of the product 5 times, then frequency is 5 and HCP count is 1....I generated frequencies from 1 to 124 in my pivot table using a calculated dimension which is working fine. But my concern is :

My manager wants frequencies till 19 in order from 1..2..3..4...5..6.....19...

And from the frequency 21-124 as 20+.

I would be grateful if someone helps me with this.....Eager for the reply....